The two most common types of panelized wood roof systems used in North America are all-wood and hybrid systems.

An all-wood system consists of glued laminated (glulam) beam girders with wood purlins (glulam, I-joists or open web wood trusses), wood sub-purlins and a wood structural panel deck. Commonly seen in buildings with spans of less than 40 feet, this system is particularly well suited for applications where conveyor equipment is hung from the roof structure or in food-processing facilities that need to minimize dust from overhead joists. It is also a good choice for developers and designers who want to take advantage of wood’s aesthetic benefits for an exposed roof structure.

The hybrid system uses steel purlin and girder trusses together with wood sub-purlins and a wood structural panel deck. The long-span capability of steel framing makes this system particularly economical when spans range from 32 to 60 feet, but much larger spans can be accommodated. Wood decking allows better economy than steel, both in terms of material and installation cost. This is usually the system of choice for large warehouse and industrial structures requiring long spans.

Tools & Support

If you’re working on a panelized roof project and could use some free technical support—or you want to learn more about panelized roof construction—email Lisa Podesto, PE, WoodWorks’ technical lead for building systems.

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Q: What if I can't find the right UL assembly for my project?

A: This situation isn't uncommon when detailing shallow framing at floors/ceilings, using structural composite lumber members or at exterior lateral resisting walls. According to the 2012 International Building Code (IBC) Section 703, fire-resistance ratings can be determined multiple ways - more